Blood clotting occurs as a result of series of complex biological interactions. There are various factors, enzymes and proteins that affect the clotting process. Long coagulation times usually indicate lack of specific factors in the blood. Various tests such PT, aPTT have been developed to identify deficiency of these specific factors. Also, patients under regular drug therapy that changes blood viscosity should be monitored for blood coagulation time. Blood coagulation time measurement provides vital information regarding the patients.
For coagulation, various testing methods have been developed to detect the beginning of the coagulation process. Optical methods detect the changes in the optical properties of blood. Electrical methods depend on resistance or capacitance change. These methods are indirect since they measure a secondary effect due to blood coagulation. Direct methods on the other hand measure the viscosity changes of the blood during coagulation. So they are more dependable and immune to other factors such as high fat concentration that may affect the optical or electrical properties of blood. US2003/0029242 discloses a device for measuring the coagulation time of blood using an ultrasonic sensor. US2009/114044 discloses a docking mechanism for a biosensor apparatus.
Coagulation time measurements are usually done at hospitals or clinical labs. Patients are required to travel to these facilities. On the other hand, point-of-care testing removes the burden on the patients. It is fast and it prevents complications that may rise due to the late or no testing.
Therefore there is a need for a portable system that can measure the blood coagulation time using a direct measurement method.